Fan module having variable-pitch blades for a turbine engine

Abstract

The invention relates to a fan module having variable-pitch blades for a turbine engine, including a rotor (2) having blades (3), a stationary casing (7), and a system for adjusting and controlling the pitch of the blades (3), the rotor (2) including a central shaft (6) and a ring (9) for supporting the blades surrounding the shaft, a front end of the ring being connected to a front end of the shaft so as to define an annular space between the ring and the shaft which is open towards the rear, said annular space of the rotor (2) housing said system, and the shaft (6) being guided by a first bearing (8) mounted in the stationary casing (7), to the rear of the ring (9), characterised in that the ring (9) is guided by at least one complementary bearing (31) located upstream of the first bearing (8).

The invention claimed is: 
     
       1. A fan module turning about an axis (X) having variable-pitch blades for a turbine engine, said fan module comprising a rotor carrying said blades, a fixed casing and a system for adjusting and controlling the pitch of the blades, the rotor comprising a central shaft and a ring supporting the blades surrounding the shaft, a front end of the ring being connected to a front end of the shaft so as to define, between the ring and the shaft, an annular space open towards the rear, said annular space of the rotor housing said system and the shaft being guided by a first bearing mounted in the fixed casing, behind the ring, characterised in that the ring is guided by at least one complementary bearing situated upstream of the first bearing with regards to rotation axis (X) and in that the system for adjusting and controlling the pitch of the blades comprises an actuator mounted on the fixed casing, said actuator comprising a housing supporting, on its external radial wall, an inner track of said complementary bearing connecting the external radial wall of the housing. 
     
     
       2. The fan module according to  claim 1 , wherein the housing is mounted on a same part of the fixed casing as the first bearing. 
     
     
       3. The fan module according to  claim 1 , wherein the housing forms a chamber inside which a piston can axially move, said piston driving a control part extending axially in front of the housing. 
     
     
       4. The fan module according to  claim 1 , wherein the system for adjusting and controlling the pitch of the blades comprises a mechanism for adjusting the pitch of the blades connected to the rotor, a control means comprising the actuator and a control part able to move in translation along a rotation axis (X) of the rotor, and a load transfer bearing between the control part and said mechanism. 
     
     
       5. The fan module according to  claim 4 , wherein the load transfer bearing is situated behind the blades. 
     
     
       6. The fan module according to  claim 4 , wherein the load-transfer bearing includes an internal track fixed to the control part and an external track fixed to a ring connected to the rotor. 
     
     
       7. The fan module according to  claim 1 , wherein the diameter of the complementary bearing is no more than the diameter of the ring. 
     
     
       8. The fan module according to  claim 1 , wherein the diameter of the complementary bearing is greater than the diameter of the first bearing. 
     
     
       9. The fan module according to  claim 3 , wherein a fixed annular track supports elastic return means arranged so as to exert an axial return force on the control part towards a given position, corresponding to a feathering position of the blades. 
     
     
       10. The fan module according to  claim 3 , wherein a fixed annular track is substantially tubular and wherein the control part slides around said fixed annular track along the rotation axis (X), the control part being linked to an internal radial periphery of the housing, and the control part extending axially forward along rotation axis (X) along the shaft. 
     
     
       11. The fan module according to  claim 10 , wherein the fixed annular track is fixed to the housing. 
     
     
       12. The fan module according to  claim 1 , wherein the first bearing includes ball bearings. 
     
     
       13. The fan module according to  claim 1 , wherein the module includes a substantially axial connecting rod mounted so to pivot on a stud at a point (A) on a crank in a direction substantially parallel to the axis (Y) of a pivot shaft. 
     
     
       14. A fan module turning about an axis (X) having variable-pitch blades for a turbine engine, said fan module comprising a rotor carrying said blades, a fixed casing and a system for adjusting and controlling the pitch of the blades, the rotor comprising a central shaft and a ring supporting the blades surrounding the shaft, a front end of the ring being connected to a front end of the shaft so as to define, between the ring and the shaft, an annular space open towards the rear, said annular space of the rotor housing said system and the shaft being guided by a first bearing mounted in the fixed casing, behind the ring,
 wherein the ring is guided by at least one complementary bearing situated upstream of the first bearing with regards to rotation axis 
 wherein the system for adjusting and controlling the pitch of the blades comprises a mechanism for adjusting the pitch of the blades connected to the rotor, a control means comprising an actuator and a control part able to move in translation along a rotation axis of the rotor, and a load transfer bearing between the control part and said mechanism, 
 wherein said actuator is mounted on the fixed casing, said actuator comprising a housing supporting, on its external radial wall, an inner track of said complementary bearing connecting the external radial wall of the housing, and 
 
       wherein the load-transfer bearing includes an internal track fixed to the control part and an external track fixed to a ring connected to the fan rotor. 
     
     
       15. The fan module according to  claim 2 , wherein said housing comprises a piston connected to a control part, said housing surrounding the control part.